1. Field of the Disclosure
This disclosure concerns an information system and techniques for processing images and associated data. In particular, an information system for handling microscopic digital images of pathology and histology samples and the like organizes and manages pathologists' workflow using a graphical user interface and visualization mechanisms that are efficiently computerized but resemble the look and feel of working with glass specimen slides, optical microscopes and patient paperwork files.
2. Related Art
Pathology is the study and diagnosis of disease through examination of organs, tissues, bodily fluids and even whole bodies (autopsies). Typically, tissue samples are taken, prepared and examined under magnification. Pathologists are physicians who diagnose and characterize disease by examining biopsies, bodily fluid, duct scrapings and similar samples. In a typical operation, tissue samples might be prepared by being sliced. The slices are mounted on glass slides or in the case of a fluid, a slide is smeared. A reagent or stain might be applied by a specialist called a histotechnician to enhance visible contrast. The sample is covered with a cover slip or cover glass. The slide is typically labeled as to sample identity, and may be associated with other slides for the same patient as well as with a patient file containing other information such as patient history information and test results. When the pathologist takes up the file, he or she reviews the available information, places the slide in a microscope, adjusts for selected viewing position, magnification, focus, etc., and examines the sample. The pathologist might take notes, make a diagnosis, call for other tests or otherwise take action.
Different pathologists may have their personal techniques, but their work has changed very little for decades. Each job unit, for example, may be a medical “case,” which is usually a single instance of a patient with a primary medical concern, has a unique file or case number. Associated with each case may be one or more specimens, which are the samples removed from the patient. The slides are standard sized glass rectangles used to hold stained tissue under a cover slip. Each slide associated with a case likewise has a unique slide number. A case may include multiple slides. The slides are usually kept in a slide tray that may have multiple slots for holding multiple slides, from which the slides are taken for viewing.
Slide trays have typically been carried around with accompanying paperwork, which might represent just part of the information associated with the patient's complete file. From the pathologist's standpoint, slide trays and accompanying paperwork are referred to as case “packages.” The case packages can be a means by which work is distributed to pathologists, for example with responsibility to attempt a diagnosis being assigned to a pathologist together with handing over custody of a case package. A pathologist knows which cases he/she is working on, and can judge workload, by the stack of case packages at his/her workstation.
A pathologists might further organize their case packages into physical piles according to categories that are meaningful to the pathologist, such as the status of the case packages in a sequence of operations, or their priority or urgency or by another category. Thus, for example, the workload could be found in several piles that include but are not limited to a “currently reviewing” pile; a “complete but not yet filed away” pile; a “signed out but waiting for follow up stains” pile; an “incomplete” pile, which may be a pile that is waiting for more slides and/or paperwork to be received; a “need to review again” pile, which may be a pile that may set aside for some reason such as to review with a trainee or other pathologist; an “educational” pile, which may be a pile that is set aside as an exemplar and possibly the subject of a conference and/or future educational reference; and the like.
Although case packages are discrete physical items that can be treated as units of workload, there are drawbacks associated with the need to handle the packages and their contents manually. For example, the physical handling and distribution of case packages may be inefficient and error prone. The physical nature of the slides and paperwork may result, for example, in breakage or misplacement of slides, “lost” case packages or package contents, a risk of mixing the contents of two or more case packages, inability to quickly find or assess the status of cases and so on. The process is characterized by many of the problems associated with manually kept files, with the additional complication of having associated slides. Manual tracking and reporting mechanisms on paper are inefficient to manage, store and monitor. It is difficult to exchange information between interested parties, difficult to archive and quickly retrieve information, and documentation or slides can become missing or misplaced. These problems reduce the pathologists' efficiency and may adversely affect patients waiting for diagnoses. Improved systems and/or processes are needed that are free of the physical constraints and manual nature of current pathology processes, that preferably provide improved reporting and mechanisms for easy and accurate data exchange, information retrieval and information processing.
There is an emerging movement toward digital encoding of microscope imaging data for use in pathology. In a technique called “whole slide imaging” the entire field of view of samples on slides is digitally imaged up to full magnification, providing a set of image file that can be selected and viewed on a computer. The opportunity for whole slide imaging to take pathology into the digital realm is enticing because after the sample has been imaged (namely after all possible views of the sample have been encoded digitally), the process can be made free of the ubiquitous glass slides. Among other benefits, whole slide imaging eliminates the burden of moving and storage of physical glass slides, permits pathologists to process cases when they are away from the slides and away from a microscope, reduces the risk of losing or mixing up patient slides and giving the wrong diagnosis to a patient, reduces the work of pathology assistants who attend to slides that come to a case package late, and may provide opportunities for computer vision algorithms to help pathologists identify specific features in the images they are viewing.
Despite the potential advantages, current digital slide viewer technology has not been widely accepted into day-to-day practice. Technical issues remain to be overcome, such as obtaining repeatably consistent image quality, dealing with the large number of image files associated with every slide, providing adequate hardware and/or software at reasonable expense to maintain image quality and processing speed and similar issues. Therefore, what is needed are digital pathology systems and/or processes that provide improved performance for processing and viewing digital images of slides.